5:15 PM - 6:45 PM
[ACG35-P03] CO2 emissions in East Asia evaluated by enhancement ratios of GHG concentrations based on GOSAT and GOSAT-2 observations
Keywords:GOSAT, GOSAT-2, fossil fuel CO2, ER
We have calculated excess concentrations of XCO2, XCH4, and XCO relative to their background concentrations (ΔXCO2, ΔXCH4, and ΔXCO) using XCO2, XCH4, and XCO data from GOSAT and GOSAT-2 observations and then calculated Enhancement Ratio (ER) by taking the ratios of the excess concentrations of two gases of the three for the three land regions in China (East China, North China, and South China) and the two ocean regions between Japan and China (East China Sea and Japan Sea) to evaluate the impact of fossil fuel CO2 emissions from Mainland China on Japanese ocean regions.
The calculated ER values and correlation coefficients of ΔXCO2/ΔXCH4 were higher throughout a year in North and East China, which is consistent with the fact that large amounts of fossil fuel CO2 are emitted throughout a year there. Over the ocean regions where there are no major CO2 and CH4 emission sources, the monthly and seasonal ER values of ΔXCO2/ΔXCH4 were the highest in February and March and in winter and spring, which is consistent with the previous study based on surface observations over Hateruma Island by Tohjima et al. [2014; 2020]. Judging from the absence of major CO2 emission sources in the ocean regions and the consistent high ER values of ΔXCO2/ΔXCH4 throughout a year in North and East China, CO2 enhancements over the Japanese ocean regions can be attributed to airmass with high CO2 concentrations emitted by fossil fuel combustion on Mainland China and transported from there by the East Asian winter monsoon.
Furthermore, backward trajectory analysis for February showed that airmasses were transported from North and East China to East China Sea and from North China to Japan Sea, which suggests the possibility of the transport of fossil fuel CO2 emitted from North and East China and North China to East China Sea and Japan Sea, respectively. Seasonal variations of ΔXCH4/ΔXCO2 evaluated based on GOSAT and GOSAT-2 observations showed good agreements to those based on surface observations over Hateruma Island by Tohjima et al. [2014], which demonstrates that our satellite-based ER analysis can also show the characteristics of the transport of fossil fuel CO2 from China to Japan, as discussed in the previous studies.
The calculated ER values and correlation coefficients of ΔXCO2/ΔXCH4 were higher throughout a year in North and East China, which is consistent with the fact that large amounts of fossil fuel CO2 are emitted throughout a year there. Over the ocean regions where there are no major CO2 and CH4 emission sources, the monthly and seasonal ER values of ΔXCO2/ΔXCH4 were the highest in February and March and in winter and spring, which is consistent with the previous study based on surface observations over Hateruma Island by Tohjima et al. [2014; 2020]. Judging from the absence of major CO2 emission sources in the ocean regions and the consistent high ER values of ΔXCO2/ΔXCH4 throughout a year in North and East China, CO2 enhancements over the Japanese ocean regions can be attributed to airmass with high CO2 concentrations emitted by fossil fuel combustion on Mainland China and transported from there by the East Asian winter monsoon.
Furthermore, backward trajectory analysis for February showed that airmasses were transported from North and East China to East China Sea and from North China to Japan Sea, which suggests the possibility of the transport of fossil fuel CO2 emitted from North and East China and North China to East China Sea and Japan Sea, respectively. Seasonal variations of ΔXCH4/ΔXCO2 evaluated based on GOSAT and GOSAT-2 observations showed good agreements to those based on surface observations over Hateruma Island by Tohjima et al. [2014], which demonstrates that our satellite-based ER analysis can also show the characteristics of the transport of fossil fuel CO2 from China to Japan, as discussed in the previous studies.